Fire extinguishing method and apparatus



March 14, 1950 D. MYERS 2,500,428

FIRE EXTINGUISHING METHOD AND APPARATUS Filed Feb. .28, 1945 4Sheets-Sheet l March 14, 1950 L. D. MYERS 2,500,428

' FIRE sx'rmcuxsnme METHOD AND APPARATUS Filed Feb. 28, 1945 v 4 sneetssiheet 2 March 14, 1950 L. D. MYERS 2,500,428

FIRE EXTINGUISHING METHOD AND APPARATUS Filed Feb. 28, 1945 4Sheets-Sheet 3 March 14, 1950 D. MYERS FIRE EXTINGUISHING METHOD ANDAPPARATUS 4 Sheets-Sheet 4 Filed Feb. 28, 1945 Patented Mar. 14, 1950FIRE EXTINGUISHING METHOD AND APPARATUS Leonard D. Myers, Washington, D.C., as si gno to Cardox Corporation, Chicago, 111., a corporation ofIllinois Application February 28, 1945, Serial No. 580,181

8 Claims, (Cl. 169-11) This invention relates to new and usefulimprovements in methods of and apparatus for discharging fireextinguishing mediums and for extinguishing fires.

The copending application, Serial No. 551,869, filed by Charles A. Getz,on August 30, 1944, amongother things, discloses and broadly claims amethodof and apparatus for discharging carbon dioxide and foam, eitherindividually or in combination, to effect the extinguishment ofcertainclasses of fires. For example, class B fires can be extinguished morequickly and effectively with an initial, brief application of carbondioxide and foam and a final, prolonged application of foam by itselfthan with either carbon dioxide or foam when used alone, or with anyother known extinguishing mediums when used alone or in any desiredcombination.

The aforesaid application specifically discloses mechanicalair foam asone of the foams that is used with carbondioxide to eifect the EX?tinguishment of fires. Mechanical air foam is produced by flowing underpressure a mixture of water and a foam stabilizing agent in such amanner that air from the, surrounding atmosphere will be drawn into theflowing mixture and entrapped in the stable bubbles of the resultantfoam;

' As all foams are broken down by flame or intense heat, it will beappreciated that when mechanical. air foam is applied directl to flameor to intensely heated surfaces in a fire zone, before the water portionof the foam has had an opportunity *to cool down these surfaces, themechanicalair foam .hubbles will be broken down andthe airentrappedtherein willbe liberated, with the result that combustionsupportingoxygen is delivere'd to the fire. This is one of the principaldifferences. between mechanical air foam andchemical foam; i. e.,thebubbles of chemical foaniare filled. with carbon dioxide vapor whichis liberated when the bubbles are broken down and has a smotheringefiect: which aidsin extinguishing afire.

Attempts have been made in the. pasttoprm duce mechanical foam whichwill not release oxygen to the fire by substituting an inert gas for theair that isdrawnintothe fiowin mixture of water tabil zin ag nt.These-prior a tempts ,have not proved satisfactory, or commer-.cially,practical,for the following reasons:

l very tq-t e ,fiowins mixture. g I e 2. Foam-bubbles formed withcompressed inert gas .entrapped therein were found to be less stable ordurable thanfoam bubbles containing air at atmospheric pressure becausethe internal pressure exerted by the compressed inert gas causedthebubbles to break down more readily.

3. Although it is entirely satisfactory to use air, instead of inertgas, after a fire isv subdued to the point where there no longer remainssufficient flame or intense heat to break down to a substantial extentthe foam bubble formation, thereby effecting a reduction in the amountof inert gas required, this saving could not be realized in connectionwith these pr-iorattempts without the addition of a suitable switchingvalve in thesupply pipe for the inert gas.

Because of the above noted objections, the manufacturers of mechanicalfoam producing equipment of today provide for the use of air as thebubble entrapped medium, and depend ona prolonged, high rate ,ofdischarge for eventually effecting the desired extinguishment.

It is the primaryobject of this invention to provide a method of andapparatus for producing a fire extinguishing discharge whichccnsists ofcarbon dioxide and mechanical foam with the bubbles of the foam havingentrapped therein carbon dioxide that is obtained from the carbondioxide portion of the discharge.

A further primary object of the invention is to provide a method of andan apparatus forproducing a fire extinguishing discharge which consistsofcarbon dioxide that has its snow and vapor components separated andmechanical air foam with the foam bubblesha'ving entrapped thereincarbon dioxide vapor that is obtained from the separated vapor componentof the carbon dioxide discharge.

A still furtherimportant. object of the invention is the provision of amethod of and apparatus for extinguishing a fire by applying thereto acombined discharge of carbon dioxide and mechanical foam, with thebubbles of the foam having entrapped therein carbon dioxide obtainedfrom the-carbon dioxide portion of the discharge, untilthe flame andtemperature conditions in the fire zone are such that the foam bubbleswill not be materially affected thereby, and then applying to the fire adischarge of mechanical air foam alone, with the bubblesof the foamhaving entrapped .therein-air obtained from the surrounding atmosphere.

Another objectof the invention is to provide a fire extinguishing methodand I apparatus for; producing a discharge of carbondioxide andmechanical foam, with the snow and vapor components of the carbondioxide separated and arranged so that the vapor component shields thesnow component from the surrounding atmosphere and with the mechanicalfoam being formed from water, a stabilizing agent, and vapor obtainedfrom the shielding vapor component of the carbon dioxide portion of thedischarge.

Still another object of the invention is to provide fire extinguishingapparatus which is operable to effect discharge of carbon dioxide alone,mechanical air foam alone, or a combination of carbon dioxide andmechanical foam which has carbon dioxide vapor entrapped in the foambubbles.

A further object of the invention is to provide apparatus for producinga fire extinguishing discharge that consists of a dense carbon dioxidesnow core, a carbon dioxide vapor envelope surrounding and shielding thesnow core, and one or more streams of mechanical foam, having carbondioxide vapor obtained from the aforesaid vapor envelope entrapped inits bubbles, arranged adjacent the margin of the carbon dioxide vaporenvelope.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings, forming a part of this specification andin which like numerals are employed to designate like parts throughoutthe same,

Figure 1 is a front elevational View of one form of fire extinguishingapparatus embodying this invention,

Figure 2 is a central vertical sectional view taken on line 22 of Fig.1,

Figure 3 is a front elevational view of a modifled form of fireextinguishing apparatus embodying this invention,

Figure 4 is a top plan view of the apparatus shown in Fig. 3,

Figure 5 is a vertical sectional view taken on line 5-5 of Fig. 3, and

Figure 6 is a horizontal sectional view taken on line 6-6 of Fig. 5.

In the drawings, wherein for the purpose of iilustration are shown thepreferred embodiments of this invention, and first particularlyreferring to Figs. 1 and 2, the reference character A designates in itsentirety the carbon dioxide discharge portion while the referencecharacter 13 designates each one of the two foam generating anddischarging portions of the complete fire extinguishing apparatusembodying this invention.

The carbon dioxide discharge portion A of this apparatus will bedescribed first.

The carbon dioxide discharge portion or nozzle A is supplied with liquidcarbon dioxide by means of the pipe line lil which may extend to anysuitable source of supply, such as a bank of high pressure cylinders oran insulated and automatically refrigerated storage tank. It ispreferred, however, to obtain the liquid carbon dioxide from theinsulated and refrigerated tank so that the liquid carbon dioxide can bedelivered to the discharge nozzle A at a predetermined, constantsubatinospheric temperature, and its corresponding low vapor pressurebecause of the higher percentage of snow yield that would be obtained.

Any suitable control valve, not shown, should be provided in the pipeline ill for starting and stopping the flow of liquid carbon dioxidethrough the latter. The pipe line ID may be of a rigid character if theapparatus of Figs. 1 and 2 is employed as a part of a fixed fireextinguishing system, or if the apparatus is associated with mobile firefighting units of the type disclosed in the Eric Geertz patent, No.2,352,379, issued June 2'7, 1944. This pipe line Ill, also, may take theform of a flexible hose line if desired. If a flexible hose line isemployed, several feet of the pipe line ill located immediately adjacentthe discharge nozzle A will take the form of a more rigid handle orplaypipe to facilitate manual handling of the apparatus.

The carbon dioxide discharge nozzle A is of the type disclosed andbroadly claimed in the patent to I-Iilding V. Williamson, No. 2,357,039,issued August 29, 1944. The liquid carbon dioxide supply pipe line 80 issuitably threadedly connected to the stem or shank H of the nozzle A.This stem or shank II is provided with a bore I2 for delivering theliquid carbon dioxide to the interior of the body portion of the nozzle.The outer or forward end it of this bore communicates with the interiorof a deflector element and cooperates with this element to form a flowpath 5 or the liquid carbon dioxide. The stem or shank i i has formed onits outer end a radially extending flange l4 formed with a circularseries of orifices 15 through which the liquid carbon dioxide isreleased to permit sudden expansion so that its pressure will drop belowpounds per square inch, absolute, which will cause a certain percentageof the liquid to flash to snow while the remainder of the liquid isvaporized. This annular flange i4 is provided with a circular series ofthreaded openings [6, for a purpose to e explained at a later point.Exteriorly, the stem or shank l l is provided with a rearwardly curvedor flared surface ll that terminates in a shoulder it.

The deflector element referred to above is identified by the referencecharacter [9 in Figs. 1 and 2. This deflector element is secured to theflange M by means of the series of screws 20 that are threaded into theholes I6 of the flange M. The deflector is partially hollowed out so asto control the direction of flow of the liquid carbon dioxide to thedischarge orifices l5. For that reason, the interior of the deflector isprovided with a conically shaped projection 2! that is axially alignedwith the bore [2 of the shank or stem II. The interior of the deflectorelement 19, radially outwardly of the spreading projection 2|, isprovided with the curved surfaces 22 that function to change thedirection of flow of the liquid carbon dioxide so that it will bedirected rearwardly through the discharge orifices IS. The inner or rearportion of the deflector element [9 is boiled or curved outwardly at 23to form an internal curved surface 24 that lies opposite to andcooperates with the curved exterior surface I! of the stem or shank ll.Fig. 2 clearly shows that these two cooperating surfaces l1 and 24diverge with respect to each other in any radial section to form anannular passageway that gradually increases in depth or thickness. Thisincrease functions to permit further expansion of the released carbondioxide so that the pressure of the same will drop still further andwill provide for flashing of whatever liquid may remain as a part of theflowing material. The outer portion of the deflector element [9 isillustrated in Figs. 1 and 2 as being formed with radial ribs 25 whichform the valleys 26 that are partially longitudinally curved so as todeflect forwardly or axially agtoogaaa 5v any-*of the discharged mediumthat "comes in contact with the same;

"The-defi'ectorelement l9, and the cooperating portion I! of the stem orshank ll, areenclosed within a chambered body or casing which is formedby-the inner portion 21 and the outer portion 28. The inner portion 210ithe body or casing is dish-shaped and is centrally cut away-"at 29 topermit the inner portionof the stem or' shank II to passtherethroughsothat the"shoulder"*l8 will act as a seator an abutment 'for"this innerportion 2'! of'thebody or casing; Any suitable means may be provided for"securing :the body or casing portion 21 to the shoulder" portion 18,such-asby-weldingor-by the use of suitable screws or both: The outerportion 28 "of "the 'bodycr casing-is of cylindrical shape'and-has'itsinner edge portion overlapping or itelescopically"associated with theouter marginal'edge portion of"the inner-body'part 21 to provide-alapped joint '30. Rivets, welding, or the like; may be employed" forrendering this joint'permanent. Figs. land 2 clearly show that thebody'or casing; of'the carbon dioxide disch'argenozzle 'cooperateswiththe stem or shank H to provide a closed rear wall while leaving thefront ofthe: apparatus entirelyopen. The body or casingadditionallycooperates with the stem or shank II and the deflector element I9 toform an annular chamber for receiving the circular series of flowcontrolling and directing unitsi3'l;

These units 3| are equally spaced around and extendradially of the stemor shank I! and the deflector element l9. Each one .of these unitsinclude a semi-circular-or semi-cylindrical band 32 which is flanged atboth of its longitudinal edges 33; see Fig. 2. The inner transverse edge34 of each one of these bands 32 is suitably anchored in closeprox'im'ityto or "in contact with theperiphery of the flaredporti'on' orsurface I! of the stem or'shank" l l. The outer edge 35 of each one ofthese. bands 32 terminatesin the plane "of the outer face of the body orcasing portion 28-and the outer edges-of the deflector element" ribs 25.

The opposite sides of each-one of these-flow controlling and directingunits 3l areformedby wall members 36 which lie inside of the edgeflanges 3-3 and are suitably; secured thereto. Figs; 1' and 2 show theopposite side walls of "eachadjacent'pair of units'3l as being formedby'a'single piece ofsheet material with the center or intermediateportion of each one of these side 'wallforming pieces designated bythereference character .31. These center or intermediate portions 31function to bridge-the gaps or spaces between the inner edges or sidesof adjacentiunits' 3|.

.Fig; 2 "clearly disclosesrtheaside walls 36 of'the several units 3|: ashaving apertures 33 formed (therein. These apertures are located in the'outer'orfront halves of the side walls 36; i. e., relativelycloseto'the'outer edges 35 of the bands .32., Each flow controlling anddeflecting unit 3.!v has mounted within the same a plow-shapeddeflecting and separating element '39. These elements' are' of V- orwedge-shape'in section with :mountingiflanges 43 formed on'the sidesthereof for securing; such as bywelding, the .elements 3.3 intheirproper placeswithin theunits 3 I. Fig.2 'discloses' these deflecting andseparating elements 39 as beingarranged with respect tothe side wallopeningsor aperturesr38 so that :the

llateralnslopingpssurfaces: 4 Loiiieachrcelement 39 will split or spreadany material iflowing through the interior of a unit 31 so that thismaterial will be deflected through the cooperating side wall openings orapertures 38. These elements the inner surfaces of the outer endportions of their associated bands 32. In other Words, a space or gap isleft between the inner surface of the band 32 of eachone of the units 3iand the outer edge 42 of its associated deflecting and separatingelement 39 through which the extinguishing medium may flow to the outeredge 35 of the band 32.

The mode of operation of thiscarbon dioxide discharge nozzle isexplained in detail in the aforesaid I-Iilding'V. Williamson patent andfor that reason its mode of operation will be only generally set forthherein. Liquid carbon dioxide, of any desired pressure and temperature,will be delivered to the bore of the shank or stem l I and'will flowas aliquid to the discharge oriflees 55. As the liquidcarbon dioxide leavesthese orifices, it expands suddenly and its pressure drops to such anextent that the liquid flashes and vaporizes. The carbon dioxide thatenters the space formed between the outwardly flowing surfaces H and 2d,therefore, takes the form of a mixture of snow and vapor. Depending uponthe temperature of the liquid carbon dioxide that is delivered to thisdischarge nozzle, a certain percentage of the same-will flash into snowas a result of the sew-cooling action that is produced. In other words,the entire discharge from the peripheral mouth, formed by the outeredges of the surfaces H and 2 will consist of a mixture of snow andvapor.

This snow and vapor mixture, as it leaves the aforesaid-peripheralmouth, will be flowing in a truly radial direction. Some portions of themixture will pass directly into the various flow controlling anddirecting units 3!. The remainder of the mixture will be split anddeflected laterally in opposite directions by the axially extendingportions 3'! of the side wall forming pieces 36. These deflectedportions of the mixture. therefore, will be directed intotheseveralunits 3i. The curved bands 32 of the flow controlling anddirecting units 3! will deflect the flowing mixture from its straightline, radial path'and convert this straight line flow into a curvilinearflow or motion. As the carbon dioxide snow of the mixture is many times"more dense than the carbon dioxide vapor, and as the velocity of bothof these components is the same, the snow'ofiers' more resistance to thedeflecting force exerted by the obstructing, curved bands 32 with theresult that the snow will. move to the outer side of. each one of thesecurvilinear flow'paths for the material. The snow, 'in seeking thisouter portion of each flow path, will'crowd or force the vapor inwardlyaway from the inner surfaces of the various bands 32. The difference indensity of the snow, as compared'to the vapor, therefore, effectsasegregation of these two components.

The snow is segregated at or close to the outer side or each one of thecurvilinear flow paths while the vaporis segregated on the inner'side ofeach path.

As the segregated snow and vapor reach the outer side of each one'of'theflow controlling and The inwardly positioned, segregated vapor, however,strikes the sloping surfaces 41 of the various elements 39 and isdirected laterally through the side wall apertures 38 into the portionsof the body or casing which lie between adjacent units 3!. Thesegregated and separated snow passes radially outwardly beyond the edges35 of the several bands 32 and is directed into the valleys 26 of thedeflector element [9. The curved inner surfaces of these valleys deflectthe snow so that it will flow, or will be discharged, to the atmospherein an axial direction with respect to the entire carbon dioxidedischarge nozzle. This discharge of all of the separated snow from allof the units 3! causes the snow to be assembled into a compact, densecore. The separated vapor will leave the spaces between the adjacentunits 3! and will flow in an axial direction relative to the dischargenozzle. The vapor is in this way discharged radially outwardly of thedense snow core. Because the areas of discharge for the vapor are spacedfrom each other by distances that equal the width of the fiowcontrolling and directing units 3i, the vapor discharges will beseparated from each other immediately adjacent the front face of thecarbon dioxide discharge nozzle. However, the various vapor dischargeswill blend together a short distance in advance of the nozzle and willform a surrounding or enclosing vapor envelope for the compact, densesnow which forms the core of the composite discharge of carbon dioxide.

From this description of the mode of operation of the discharge nozzlefor the carbon dioxide, it will be appreciated that there is provided adischarge stream which is of substantially circular or cylindrical shapein transverse section. In Fig. 2 of the drawings, the dotted lines D areintended to represent the peripheral margin of the compact, dense snowcore. All of the carbon dioxide that is discharged radially outwardly ofthese lines D, therefore, will be the separated carbOn dioxide vaporthat forms the snow shielding envelope.

The foam generating and discharging portions B of the fire extinguishingapparatus disclosed in Figs. 1 and 2 now will be described in detail.

It will be noted from the two figures of the drawings that the two foamgenerating or discharge portions, or guns, B are located ondiametrically opposite sides of the carbon dioxide discharge nozzle Aand that these foam guns are structurally or operatively associated witha substantial portion of the periphery of the carbon dioxide nozzle. Itwill be appreciated that the size of the various elements thatconstitute each one of these foam guns will determine to a considerableextent the volume or quantity of foam that is generated and discharged.Therefore, if a greater total volume of foam is desired for certainextinguishment work, three or more foam guns B can be provided anddistributed or spaced equal distances from each other around theperiphery of the carbon dioxide discharge nozzle A. Additionally, if alesser amount of foam is desired, one of the two foam guns B,illustrated in Figs. 1 and 2, can be dispensed with.

Each one of these foam guns is illustrated as having a pipe line 45which is employed for supplying a suitable mixture of water and anydesired, commercial foam stabilizing agent. This mixture, also, caninclude a suitable anti-freeze material or chemical when the fireextinguishing apparatus is used under ambient temperature conditionsthat would cause the water to freeze.

The water and stabilizing agent mixture can be supplied from anysuitable source and is intended to flow through the pipe lines 45 underany desired pressure. It will be noted that these pipe lines areintended to extend longitudinally of and to be grouped with or attachedto the carbon dioxide supply pipe line I0. Additionally, these foammixture pipe lines 45 curve around or radially and axially of theperiphery of the carbon dioxide discharge nozzle A. These pipe lines 45,therefore, will be flexible or rigid depending upon the character of thepipe line It and the use to which the fire extinguishing apparatus isapplied; i. e., incorporated in a fixed fire extinguishing system orused as a discharge device for a hose line.

Each one of the pipe lines 45 extends to and is suitably connected witha coupling or discharge manifold 46. This coupling or manifold ishollowed out and is provided with a suitable number of orifice tips 41mounted in its front wall 48 and adapted to discharge the water andstabilizing agent mixture or solution from the coupling or manifold. Asuitable strainer element 49 is mounted in the element 46 and functionsto separate out foreign matter and solid particles that might clog thetips 41.

Suitably attached to the discharge end of the coupling or dischargemanifold 46 is a hollow member 50 that functions to provide a foamgenerating chamber 5| and a pick-up spout 52. This pick-up spout portion52 of the member 50 is illustrated in Figs. 1 and 2 as extending to theannular space formed within the outer portion 28 of the body or casingand the peripheries of the associated flow controlling and directingunits 3|. That is to say, the outer halves of these units 3| curveradially inwardly away from the body or casing portion 28 to providespace for the inlet throat 53 of the pick-up spout 52.

Fig. 1 shows this inlet throat 53 of each pickup spout 52 as beingaligned with three of the carbon dioxide vapor discharge spaces that areleft between the flow controlling and directing units 3!. Therefore,when carbon dioxide vapor is being discharged by the carbon dioxidenozzle A, some of this vapor will enter each one of the two pick-upspouts 52 and this vapor will be delivered to the foam generatingchambers 5|.

The bringing together of the carbon dioxide vapor and the mixture orsolution of water and foam stabilizing agent in the chambers 5i causesfoam to be produced. This foam has the carbon dioxide Vapor entrapped inits bubbles. The foam generated in each chamber 5| is discharged throughthe associated foam delivering and directing tube 54.

These delivering and directing tubes 54 are illustrated in Figs. 1 and 2as having their axes arranged in parallelism with the axis of the carbondioxide discharge nozzle A. It will be appreciated, however, that thesefoam tubes 54 may be positioned so that their axes will form eitheracute or obtuse angles with respect to the axis of the carbon dioxidedischarge nozzle A. If the axes of the foam directing tubes 54 arearranged at acute angles with respect/to the axis of the carbon dioxidedischarge nozzle A, the resultant foam streams will be directed into thecarbon dioxide stream for being blended with or entrained by the carbondioxide. If the axes of the foam directing tubes 54 form obtuse angleswith respect to the axis of the carbon dioxide discharge nozzle A, thefoam streams will be caused to diverge or spread out relative to the acombined .dischargeof carbon dioxide and foam by openin all ofsaid.valves. If it is desired to: discharge only" carbon dioxide, the controlvalves-for thersupply pi-pe'lines 45 will be closed. If zrit .is desiredtowdischarge only. foam, the corn trol valves for. the: ipe lines 45will-be opened and the control valve for the :carbon dioxidesupply'line- ID will be closed; As'no carbon dioxide vapor will bedischargedlbyrthe nozzle A under this lastmentioned operating condition;the pick- 11p'Sp011tSf52 will not receive. any'carbon dioxide vapor.However, the aspirating; action produced by the discharge of I water anda .foam r stabilizing agent from the orifice tips. through the gencratingchamber 5land: into thealigned'foam delivering" and directingtube, 54 willcause air from the surrounding atmosphere-to be drawn into.each pick-up. spout 52 through its inlet throat 53;. This atmosphericair Willi be delivered to, the foam generating chambers 5land will beentrappedinthe bubbles of the foam produced in these chambers.

Figs. Sto 6. inclusivev disclose amodified form of, fire fightingapparatus which. is dsignedfor producing acombined discharge. of carbondioxideand foam or discharges-of carbon dioxide by itselfanddischargesof fOambyitself. The difference between the dischargesproducedb'y the apparatus of Figsv 3 to 6 inclusive and the apparatus.of' Figs. 1 and- 2 relates primarily to the cross sectional shape" of."the discharge streams; With the apparatusof Figs. 1 and21 thecarbondioxide stream and the". foamstreams are each'of circular" crosssection: With 5. the" apparatus of Figs. 3to"6"inclusive', the singlecarbon dioxide stream and each one of the several foam streams is ofelongated shape'in cross section; or'with each stream having a Imajorand a' minor cross sectional dimension. Thetype of dischargeprovided by the apparatus of Figs. 3*to 6 inclusive is best suited'forextinguishing ground fires or for applying the extinguishing medium overa large surface area ofa pool or 'confinedbodyof-fiam' .m'able fluid.Due 'to'the large surface coverage provided by the apparatus of Figs. 3to 6 inc1usive; this apparatus'can be installed in a fixed positionwith'respect -to'thehazard or it"can be mounted onthe front" ofaflmobile firefighting unit;

rangement'of-the'foam: guns H 1 with respect to T the. =carbon :dioxidenozzle-G: A's-illustrated; .two of.;the foam guns are associatedwiththe-upper longitudinal imarginof .1 the. carbon 'dioxidesnoze zlewhile two additionall foam guns 2: are? assor ciatedziwiththedowerrlon'gitudinal marginm" thecarbon diOXidB IIOZZIGw Each one ofthese longitudinally aligned pairs of foam guns extendsthroughouta-major portion of the lengthof the carbon dioxide (nozzle. Itwill be appreciated that the combined length of each aligned pair offoam guns "may be increased or decreased as desired to vary the volumeof foam that is generated with reference to the volumeof carbon dioxidethat is discharged by the nozzle G.- Additionally, either the upper orthe lower pair of foam guns may be dispensed with if only one pair offoam guns is required, or will produce a sufficient quantity of .foamfor a given type of hazard. Under certain operating conditions, it maybe necessary-to employ only one ofthese foam guns H in combination withthe carbon dioxide discharge nozzle G. When only one foam gun-isemployed-it, preferably, will be centrally located with" respect to-thelength of the carbon dioxide nozzle G and it may be associated witheither the top or the bottom longitudinal margin of the carbon dioxidenozzle.

The-carbon dioxidenozzle portion of this fire extinguishing apparatus isbest illustrated in Figsiii to 5 inclusive and the detail structuralfeatures will be describedin'connection with these figures.

This carbon dioxidetnozzle G is-of the same general construction as:that disclosed. in the Hilding. V. Williamson Patent No. 2,357,040,issued August 29, 1944. This nozzle includes a supplypipe line 55*whichis employedfor deliver-- ing liquid carbon dioxide to' the nozzle. Thispipeline may receive it's'liquid carbon dioxide from'either a bank orhigh pressure cylinders, or from a'single insulatedandautomaticallyrefrigerated storage tank in the same manner as has beendescribed in connection with the carbon dioxide nozzle A of Figs. 1 and2'. The forward end of the pipe line 5511s connected to the rightangularly arranged branches 56and 51. These branches extend in oppositedirections and are suitably connected to the intermediate portions of"discharge pipes 58 and 59 respectively. The

pipes 58 and 59 are illustrated in Figs. 3 and 5 a's'being arranged inparallelism with respect to each other. These discharge pipesaresuitably closed at their opposite outer ends and each pipe is" providedwith a longitudinallyarranged series of discharge apertures or orifices66. Fig. 5di scloses these orifices or apertures as facin in a generallyrearward direction, rather than a forward direction, and'it is to beunderstood a that the apertures or orifices may be spacedat any. desiredor suitable distance from each other.

Each one of these apertured discharge pipes 5-8 and 59. isfarrangedwithin a merging and segregating chamber 6!. These chambers are arrangedin parallelism with each other and each one. is provided with a curvedrear Wall 62 that is joinedtothe side, parallel walls 53. Each oneofthese chambers 61 is entirelyopen at itsfront, orat the portion oppositeits-curved rear wall w, and: both endsof these chambers 75 to the *outersurfaces 'of the curved inner-walls 11 B2 of the chambers for furtherinterconnecting these two chambers.

By inspecting Fig. 5, it will be seen that the longitudinal series ofdischarge orifices or apertures 60 of each discharge pipe 58 or 59 pointor face in the general direction of the zone or region where itsassociated rear, curved chamber wall 62 merges with the outer sidechamber wall 63. The importance of this direction of discharge will beapparent as the description, proceeds.

The mode of operation of this carbon dioxide discharge nozzle now willbe described. Liquid carbon dioxide of any desired temperature, andcorresponding vapor pressure, will flow under its own vapor pressurethrough the pipe line 55 and the branch lines 56 and 51 to the paralleldischarge pipes 58 and 59 respectively. The liquid carbon dioxide inthese discharge pipes will be released to the interiors of the chambers5| through the constricted orifices or apertures 60. Due to the suddendrop in pressure which occurs as a result of releasing the liquid carbondioxide in this manner, the liquid is converted to a mixture of snowparticles and vapor. Each aperture or orifice 60 will provide a separatejet or stream of this carbon dioxide mixture. These jets or streams willpartake of straight-line motion until their paths are obstructed by theinner surfaces of the chamber walls. The curved formation of eachchamber rear wall 62 will cause the flowing mixtures of carbon dioxidesnow and vapor to be deflected so that the said normal straight-linemotion will be converted to a curvilinear motion. In addition topartaking of this curvilinear motion, the snow and vapor mixtures of theseveral streams or jets released into each one of the chambers 6| willbe permitted to spread longitudinally of their chamber with the resultthat the several jets of mixture will merge to form a continuous massequal in length to each chamber 6|.

The curved surfaces of the rear chamber walls 62 will function to changethe direction of motion of the released carbon dioxide snow and vapor.Because the carbon snow of the mixture is many times more dense than thecarbon dioxide vapor, and because the velocity of both of thesecomponents is the same, the snow offers more resistance to thedeflecting force provided by the rear, curved chamber walls. The snow,therefore, will force its way to the outer side of the curvilinear pathof flow of the material with the result that it will displace the vaporor force it to seek a path of flow away from the interior surface of thechamber walls. The difference in density of the snow, as compared to thevapor, therefore, brings about a segregation of these two components; i.e., the show will form a flowing layer in contact with the inner wallsurface of each chamber while the vapor forms a superimposed layer thatis spaced from the surface of the chamber wall.

The desired segregation of the snow and vapor is accomplished by thetime the discharge reaches the open front of each one of the chambersBI. The snow layer for each chamber will be arranged adjacent the innerside wall 63 while the vapor layer will be arranged outwardly of thesnow layer, or adjacent the discharge pipe 58 or 59. The final carbondioxide discharge stream, therefore, will be formed by the segregateddischarges from the two parallel chambers. The snow layers from the twochambers will lie adjacent to each other and immediately will merge. Thevapor layers of the two discharges will be located out- 12 wardly of, orabove and below, the merged snow layers and will sandwich the snowtherebetween. It will be appreciated, therefore, that the final carbondioxide discharge will consist of a core that is formed by the twomerged snow layers with the vapor layers shielding the snow core fromthe surrounding atmosphere. This final discharge stream will have awidth which corresponds with the length of each chamber while the depthor thickness of the final stream will be approximately equal to thedistance between the adjacent sides of the discharge pipes 58 and 59.

Each one of the foam generating and dischar ing guns H of the apparatusshown in Figs. 3 to 6 inclusive will function in the same manner as thefoam guns B of the apparatus shown in Figs. 1 and 2. Therefore, thedescription of the foam guns H will be presented as briefly as possibleand will serve the purpose of only specifically describing thedifferences in structural design.

Each one of these foam generating and discharging guns is provided witha supply pipe line 5! that delivers a mixture of water and a foamstabilizing agent to the coupling or discharge manifold 68. Thiscoupling or manifold of each gun is of elongated formation inlongitudinal section. It is hollowed out, or chambered, so as touniformly deliver the mixture of water and stabilizer to thelongitudinally aligned series of orifice jets 59. These jets function todeliver the mixture into the foam generating chamber ll) of each gun. Asuitable strainer H is provided at the entrance or inlet for eachcoupling or discharge manifold 68 to separate out solid particles offoreign matter that might clog up the jets 69.

The foam generating chambers 10 of the two guns H are formed in themembers ll Which are so shaped as to provide pick-up spouts l2. Thesepick-up spouts are provided with inlet throats 13 that are arranged toreceive carbon dioxide vapor from their respective segregating chambers6|.

This picked-up carbon dioxide vapor is delivered to the foam generatingchamber ll] of each member H and is so mixed with the water and foamstabilizing agent solution that the resultant foam has the carbondioxide vapor entrapped in its bubbles. This generated foam isdischarged to the delivering and directing tubes 14. By inspecting theseveral figures, it will be seen that these tubes 14 are of elongatedshape in transverse section or are provided with major and minor crosssectional dimensions.

As was noted in connection with the fire eX- tinguishing apparatus ofFigs. 1 and 2, the foam guns H of the apparatus shown in Figs. 3 to 6inclusive will function to produce ordinary mechanical air foam when thecarbon dioxide nozzle G is not operating. That is to say, the pickupspouts 12 will have air from the surrounding atmosphere drawn therein bythe aspirating action produced by the discharges of water and a foamstabilizing agent delivered by the orifice tips 69.

1 It is to be understood that I do not desire to be limited to the exactorder of method steps as they have been disclosed, for variations andmodifications of the same, which fall within the scope of theaccompanying claims, are contemplated. It further is to be understoodthat the particular types of apparatus herein shown and described aretobe taken as preferred examples of the invention, and that variouschanges in the shape, size, and arrangement of parts may be resorted towithout departing from the spirit of the invention or the scope of thesubjoined claims.

Having thus described the invention, I claim:

1. A method of discharging a fire extinguishing medium, comprisingeffecting sudden release of liquid carbon dioxide to lower itstemperature sufficiently to form a discharge stream of snow and vapor,separately generating foam by mixing carbon dioxide diverted from theaforesaid discharge stream with a mixture of water and a foamstabilizing agent flowing under pressure, and projecting the generatedfoam as a stream in such an associated relation with respect to thecarbon dioxide stream that the carbon dioxide and foam will besimultaneously applied to the same general area of a'fire.

2. A method of discharging a fire extinguishing medium, comprisingeffecting sudden release of liquid carbon dioxide to lower itstemperature sufiiciently to form a mixture of snow and vapor, separatingthe snow and vapor components from each otherand forming them into acomposite discharge stream, separately generating foam by mixing carbondioxide vapor diverted from the aforesaid composite discharge streamwith a mixture of Water and a foam stabilizing agent flowing underpressure, and projecting the generated foam as a stream in such anassociated relation with respect to the carbon dioxide stream that thecarbon dioxide and foam will be simultaneously applied to the samegeneral area of a fire.

3. A method of discharging a fire extinguishing medium, comprisingeffecting sudden release of liquid carbon dioxide to lower itstemperature sufficiently to form a mixture of snow and vapor, separatingthe snow and vapor components from each other and forming them into acomposite discharge stream with the vapor shielding the snow from thesurrounding atmosphere, separately generating foam by mixing carbondioxide vapor diverted from the vapor shielding portion of the aforesaidcomposite stream with a mixture of water and a foam stabilizing agentflowing under pressure, and projecting the generated foam as a stream insuch an associated relation with respect to the carbon dioxide streamthat the carbon dioxide and foam will be simultaneously applied to thesame general area of a fire.

4. A method of discharging a fire extinguishing medium, comprisingdischarging carbon dioxide snow and vapor into the atmosphere in theform of a stream, completely generating foam at a location removed fromthe stream of carbon dioxide by mixing water, a foam stabilizing agentand carbon dioxide diverted from the aforesaid stream to said foamgenerating location, and projecting the generated foam as a streamparalleling and flowing in the same direction as the carbon dioxidestream.

5. Fire extinguishing apparatus, comprising means for producing anddischarging a stream of carbon dioxide snow and vapor, a foam generatingchamber, means for delivering to said chamber a mixture of Water and afoam stabilizing agent, means for delivering to said chamber carbondioxide withdrawn from the carbon dioxide stream, and means fordischarging and directing the generated foam from said chamber as astream flowing in the same general direction as the carbon dioxidestream.

6. Fire extinguishing apparatus, comprising means for producing anddischarging a stream of carbon dioxide snow and Vapor, a foam generatingchamber closely adjacent the aforesaid means, means for delivering tosaid chamber a mixture of Water and a foam stabilizing agent, means fordelivering carbon dioxide vapor to said chamber for entrapment in thebubbles of the foam, and means for discharging the generated foam fromsaid chamber as a stream flowing in the same general direction as thecarbon dioxide stream.

7. Fire extinguishing apparatus, comprising means for producing anddischarging a stream of carbon dioxide snow and Vapor, means fordiverting carbon dioxide vapor from said stream, and means for producingand discharging in close proximity to the carbon dioxide stream a foamstream having entrapped in its bubbles the carbon dioxide vapor divertedfrom the carbon dioxide stream.

8. A method of extinguishing a fire, comprising the steps of firstapplying to the fire area a combined discharge of carbon dioxide and afoam which is completely generated, at a location removed from thedischarged carbon dioxide, by mixing a foam stabilizing agent and carbondioxide diverted from the aforesaid discharge, and, after the fire hasbeen subdued sufliciently to permit the foam bubbles to remain intact,then applying to the fire area a discharge of foam having air from thesurrounding atmosphere entrapped in its bubbles.

. LEONARD D. MYERS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,352,399 Myers June 27, 19442,387,935 Myers Oct. 30, 1945 2,387,963 Williamson Oct. 30, 19452,414,683 Williamson Jan. 21, 1947 FOREIGN PATENTS Number Country Date658,328 Germany Mar. 10, 1938

